The increasing energy demands of the global economy require the identification of new hydrocarbon reservoirs as well as the maximization of hydrocarbon recovery from existing reservoirs. The identification and recovery of the vast deposits of hydrocarbons trapped within subterranean reservoir formations have long been recognized as a challenge to the industry. The accurate identification and characterization of shale gas flow is critical for assessing and maximizing shale gas recovery in challenging environments such as tight shale formations comprising shale gas enriched with organic based material.
The use of pulse-decay permeability measurements for the characterization and modeling of subterranean shale gas flow has previously been described, e.g. in Jones, “A Technique for Fast Pulse-Decay Permeability Measurements in Tight Rocks,” SPEFE (March 1997) 19-25; Darabi et al., “Gas Flow in Ultra-Tight Shale Strata,” Journal of Fluid Mechanics 710, 641-658 (2012) and Dicker et al., “A Practical Approach for Determining Permeability from Laboratory Pressure-Pulse Decay Measurements,” 1988 SPE International Meeting on Petroleum Engineering (Paper SPE 17578).
However, these methodologies and techniques have well defined limitations in shale gas identification and analysis, particularly with regard to the characterization and modeling of shale gas flow within the numerous types of pore systems that can exist in a reservoir, including “fast-flow” and “slow-flow” pathways. The need therefore exists for improved methods and techniques for assessing subterranean shale gas reservoirs and deposits for enhancing natural gas recovery.